Rodents such as rats are not only a nuisance, but can be extremely costly wherever food is stored or transported, consuming vast amounts of grain and other foodstuffs. Furthermore, rats spread disease, and can be dangerous to domestic animals and humans. Many modem rodenticides are slow-acting chemical substances which are dispensed with food which is attractive to rodents. Preferably the rodenticides do not cause immediate rodent death, hence avoiding evidence at the rodenticide dispensing area of the lethality of the apparently desirable rodent bait. To maximize rodenticide effectiveness at a particular infested region, the bait and rodenticide mixture is dispensed within a container which may be fixed in place. These dispensers or bait stations enclose the bait, keeping it dry and preventing the displacement of the rodenticide. Bait stations must make the bait easily accessible to rodents, but at the same time must restrict access to the rodenticide by domestic animals and children. For durability and low cost, bait stations have advantageously been formed as unitary injection-molded plastic units, with a plastic lid joined by an integrally molded hinge to a plastic base. Bait stations for extermination of mice have formed the barrier within the station by an upwardly extending wall which is closely spaced from or in abutment with the lid. Bait stations for use with rats, however, must be significantly larger than those used with mice, and a single walled plastic barrier is usually not sufficiently stiff to provide the necessary resistance to crushing. Furthermore, the limitations of injection molding make it particularly difficult to mold deep solid walls on the interior of a container. Larger bait stations have formed barriers by molding a double-walled structure which extends from the base floor. Double walls, in certain applications, are susceptible to trapping dirt and debris, and are hence less amenable to cleaning.
What is needed is a low cost, stiff rodent bait station which is large enough to accommodate rats.